Mounts for an optical structure having a grooved protruding member with a damping ring disposed in or on the groove and methods of mounting an optical structure using such mounts

ABSTRACT

An improved mount for, and method of mounting, an optical structure having a grooved/relieved protruding member with a damping ring therein or on is provided. The grooved/relieved protruding member may extend from the optical structure, and an upper element having a first opening extending therethrough may receive at least a portion of the grooved/relieved member in the first opening. The upper element may include second and third openings therein that operate along with the first opening and a tightening mechanism. Tightening of the tightening mechanism into at least one of the third opening and the second opening causes the ends of the head portions to draw toward each other so that the first opening of the upper element tightens around the at least a portion of the grooved/relieved protruding member.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation non-provisional patent application of U.S. patent application Ser. No. 14/186,242, filed on Feb. 21, 2014, and claims the benefit of the filing date of, and priority to, U.S. Provisional Application No. 61/767,489, filed Feb. 21, 2013, the entirety of which applications are incorporated herein by reference.

BACKGROUND OF THE INVENTION

This invention relates to the field of mounts for optical structures, including but not limited to, reflective panels, optical filters (absorptive and/or dichroic), hollow retroreflectors and solid retroreflectors.

Optical structures such as, but not limited to, reflective panels (mirror panels), optical filters (absorptive and/or dichroic), hollow retroreflectors and solid retroreflectors are old in the art. Solid retroreflectors are solid tetrahedrons of glass wherein three adjacent sides of the tetrahedron are substantially perpendicular to each other and these three sides that meet at a common corner are polished to have a high degree of flatness. Hollow retroreflectors are made of three mirror panels joined together preferably having optically flat reflective surfaces disposed at right angles to each other, and meeting at what can be described as a common inside corner of an imaginary cube. Both solid and hollow retroreflectors in general have the essential property of causing incident and reflected light rays to travel along substantially parallel paths.

When hollow retroreflectors are assembled for high accuracy and precision it is important to maintain the mutual perpendicularity of the reflective surfaces and sometimes essential to ensure that the retroreflector as a whole does not move. The perpendicularity of the reflective surfaces is affected by external stresses. With regard to high accuracy and precise reflective panels, such as mirror panels to be used for high accuracy purposes, it is also important to try to maintain as optically flat as possible the reflective surface of the panel.

Examples of external stresses that can affect the optical flatness of a reflective panel, an optical filter and/or the perpendicularity of reflective surfaces of abutting reflective panels of a hollow retroreflector, are thermal expansion or contraction of the substrate material from which the panels are made, deflection caused by curing of the adhesives used to join elements together and/or to join the retroreflector to its mount and/or the mass of the panels themselves. Accordingly, it would be desirable to assemble together the elements of a hollow retroreflector or of an optical filter, and/or to assemble a reflective panel to a mount, in such a manner as to reduce these stresses. It would also be desirable that the manner of mounting an optical filter, reflective panel(s) and/or a retroreflector to its mount not add to these stresses, but nevertheless, securely retain the optical filter, reflective panel(s) and/or retroreflector on the mount. Examples of hollow retroreflector mounts which have proven successful in maintaining the reflective surfaces in their perpendicular orientations are found in U.S. Pat. No. 3,977,765, to Morton S. Lipkins, U.S. Pat. No. 5,122,901, to Zvi Bleier, and U.S. Pat. No. 5,335,111, also to Bleier.

Additionally, any prior art mounts that may include flexible materials cannot, and do not, maintain the dimensional stability (“DS”) such that various forces working on a connected optical structure may be constantly changing the dimensions of that optical structure.

The present mount also achieves secure mounting of the optical structure in a manner designed to help eliminate deflective stresses on the reflective surface(s) of the structure caused by the mounting of the optical structure, such as the optical filter, the reflective panel(s) and/or the retroreflector to its mount. One or more aspects of the present mount also achieve dimensional stability (“DS”) such that a “hard mount” is achieved. One or more further aspects of the present invention permit the hard mounts to maintain any provided degree of flatness (e.g., at least about λ/4, at least about λ/10, between about λ/4 and about λ/30, etc.) and more particularly, to maintain a high degree of flatness (e.g., at least about λ/20, at least about λ/15, between about λ/15 and about λ/20, between about λ/15 and about λ/30, etc.) after the mount is constructed.

The mount also allows for easy and secure mounting of the optical structure onto a support structure.

SUMMARY OF THE INVENTION

In accordance with the invention, an improved mount for, and method of mounting an optical structure is provided. The mount has a protruding member extending from a surface of the optical structure, a base element having a mounting structure for mounting the mount to another structure and an upper element extending from the base element having a first opening extending therethrough for receipt therein of at least a portion of the protruding member. In one or more embodiments, the mount has a protruding member extending from a surface of the optical structure and an upper element having a first opening extending therethrough for receipt therein of at least a portion of the protruding member. The mount may further include a base element having a mounting structure for mounting the mount to another structure where the upper element may extend from the base element. The first opening defines first and second arms, each of the arms comprising a head portion and each of the head portions ending at an end. A second opening in the upper element extends through one of the head portions and the end thereof in a direction toward the other head portion, while a third opening exists in the upper element through the end of the other head portion in an orientation substantially opposite to and in communication with the second opening so that a tightening mechanism received through the second opening can be received into the third opening. Tightening of the tightening mechanism into the third opening causes the ends of the head portions to draw toward each other so that the first opening of the upper element tightens around the at least a portion of the protruding member.

In accordance with at least another aspect of the invention, the protruding member may have a first portion extending from a surface of the optical structure, a second portion, and a groove defining the first and second portions on each side of the groove, thereby permitting the groove and/or the protruding member to dissipate and/or eliminate one or more stresses passing through the mount and affecting the optical structure. Tightening of the tightening mechanism into the third opening may cause the ends of the head portions to draw toward each other so that the first opening of the upper element tightens around the at least second portion of the protruding member. The groove may be disposed on the protruding member such that the first portion is smaller than the second portion. The groove may be constructed on the protruding member such that the groove is spaced away from the optical structure and is located on the protruding member at a predetermined distance from the optical structure and/or from the top surface of the protruding member. The first portion of the protruding member may be smaller, substantially equal to, or larger than the second portion of the protruding member.

The method of mounting the optical structure onto the mount is to form an optical structure having a reflective surface and a portion of the mount comprising a protruding member extending from a back surface of the optical structure, wherein the protruding member is either integrally formed with, or bonded to, the back surface of the optical structure. Forming the remainder of the mount comprising a base element having a construction for allowing the mount to be mounted to another structure, the mount further having an upper element having a first opening extending therethrough, such first opening forming two arms each having a head portion and ending at ends thereof. In one or more embodiments, the remainder of the mount may comprise the upper element having a first opening extending therethrough, such first opening forming two arms each having a head portion and ending at ends thereof (e.g., without a base element), and the upper element may operate to allow the mount to be mounted to another structure (e.g., the upper element may include structure similar to the structure disclosed herein for the base element (e.g., threaded holes and/or members attached thereto); the upper element may include structure operating to permit the upper element to be attached or connected to a base element as disclosed herein; etc.). Sliding the first opening of the mount over at least a portion of the protruding member. Tightening the first opening of the mount around the protruding member by inserting a tightening mechanism into a second opening located through one of the head portions of the mount and by further inserting and tightening the tightening member into a third opening in the other head portion of the mount so that the tightening member draws the two ends of the head portions toward each other thereby contracting the first opening of the mount around the protruding member of the optical structure.

In accordance with at least an additional aspect of the invention, the method of mounting the optical structure onto the mount is to form an optical structure having a reflective surface and a portion of the mount comprising a protruding member extending from a back surface of the optical structure, wherein the protruding member is either integrally formed with, or bonded to, the back surface of the optical structure. The protruding member may have a first portion extending from the back surface of the optical structure, a second portion, and a groove defining the first and second portions on each side of the groove, thereby permitting the groove and/or the protruding member to dissipate and/or eliminate one or more stresses passing through the mount and affecting the optical structure. Tightening the first opening of the mount around the at least second portion of the protruding member by inserting a tightening mechanism into a second opening located through one of the head portions of the mount and by further inserting and tightening the tightening member into a third opening in the other head portion of the mount so that the tightening member draws the two ends of the head portions toward each other thereby contracting the first opening of the mount around the at least second portion of the protruding member of the optical structure. The groove may be constructed in between the first and the second portions of the protruding member such that the first portion is smaller than, substantially equal to and/or larger than the second portion. The groove may be constructed on the protruding member such that the groove is spaced away from the optical structure and is located on the protruding member at a predetermined distance from the optical structure and/or from the top surface of the protruding member.

In accordance with yet another aspect of the invention, at least one embodiment of the mount, and similarly at least one embodiment of the method of mounting, may further involve one or more reliefs (also referred to as notches or depressions) that may be formed in and/or on (e.g., in communication with, as part of, etc.) the perimeter of the recess of the mount or may be formed on/in/around the perimeter (e.g., in communication with, as part of, etc.) in the bottom portion of the protruding member, thereby reducing physical contact, and, thus, the transfer of pressure or stresses/forces between the mount and the protruding member. The one or more reliefs may be in communication with at least one of: (i) the first opening, the one or more reliefs being positioned in and/or on a perimeter of the first opening and the one or more reliefs operating to reduce physical contact between one or more surfaces of the protruding member and one or more surfaces of the upper element of the mount, thereby reducing and/or eliminating transfer of one or more stresses between the upper element of the mount and the protruding member; and (ii) at least the second portion of the protruding member, the one or more reliefs being positioned in and/or on a perimeter of at least the second portion of the protruding member and the one or more reliefs operating to reduce physical contact between one or more surfaces of the protruding member and one or more surfaces of the upper element of the mount, thereby reducing and/or eliminating transfer of one or more stresses between the upper element of the mount and the protruding member. Preferably, the one or more reliefs are radial reliefs (e.g., extending from an outside surface inwardly towards the center of the protruding member, extending from an interior surface of the recess in the mount outwardly towards an outside surface of the mount, etc.). The one or more reliefs may extend a predetermined distance radially from the first opening towards an exterior of the upper element when the one or more reliefs are positioned in and/or on the perimeter of the first opening. Additionally or alternatively, the one or more reliefs may extend a predetermined distance radially from the at least second portion of the protruding member towards an interior of the protruding member when the one or more reliefs are positioned in and/or on the perimeter of at least the second portion of the protruding member.

In accordance with yet another aspect of the invention, at least one embodiment of the mount, and similarly at least one embodiment of the method of mounting, may further involve and/or include a damping ring disposed in, connected to and/or adhered to at least one of the groove, the protruding member and the optical structure. One or more embodiments of the mount, and the method of mounting, may include at least one of: (i) the damping ring operates to dampen said one or more stresses affecting the grooved protruding member, thereby improving the stress resistance of the grooved protruding member; (ii) the damping ring operates to handle tension and to stretch and/or flex at and/or on one portion of the damping ring while compressing at and/or on another portion of the damping ring, thereby improving the stress resistance of the grooved protruding member; (iii) the damping ring is flexibly resilient such that the damping ring operates to return to its rest position and/or original configuration in the grooved protruding member when said one or more stresses are not acting on the damping ring; (iv) the damping ring comprises polyurethane and/or any other compound or material which shows one or more large mechanical losses, thereby at least one of reducing motion, dampening the one or more stresses affecting the grooved protruding member and damping one or more results of the mount; (v) the damping ring operates to reduce the tendency of at least one of the grooved protruding member and the groove to stretch and/or compress; (vi) at least one of one or more portions of the grooved protruding member and one or more portions of the damping ring bend along, transversely to and/or away from an axis of the grooved protruding member and/or a plane including the axis of the grooved protruding member, the axis of the grooved protruding member extending through the first portion and the second portion of the grooved protruding member; (vii) at least one of one or more portions of the grooved protruding member and one or more portions of the damping ring bend along, transversely to and/or away from a longitudinal axis of the grooved protruding member and/or a plane including the axis of the grooved protruding member, the longitudinal axis extending through a surface of the first portion of the grooved protruding member that is in contact with the optical structure and through a surface of the second portion of the grooved protruding member, the surface of the second portion of the grooved protruding member being located on the opposite side of the grooved protruding member from the surface of the first portion of the grooved protruding member and the surfaces of the first and second portions of the grooved protruding member being substantially parallel to each other; (viii) the one or more large mechanical losses comprise a conversion of motion to heat, thereby reducing any motion of the grooved protruding member and/or any other portion of the mount that would result from the one or more stresses and dampening the one or more stresses affecting the grooved protruding member; and (ix) said one or more stresses comprise at least one of: connection and/or clamping stress in between said first and second arms, stress from said tightening of said tightening element, stress from rotating said tightening element, stress passing through said base element, stress passing through said upper element, stress passing through said protruding member, sheer stress, rotational stress and vibrational stress.

In one or more embodiments of the mount, and method of mounting, the damping ring may have at least one of the following structural features or attributes: (i) the damping ring is adhesively adhered to the grooved protruding member; (ii) the damping ring is adhesively adhered to the optical structure; (iii) the damping ring is adhesively adhered to the grooved protruding member on and/or at at least one surface of the damping ring; (iv) the damping ring is adhesively adhered to the grooved protruding member on and/or at at least two surfaces of the damping ring; (v) the damping ring is adhesively adhered to the grooved protruding member on and/or at at least one surface of the damping ring and to the optical structure on and/or at at least another surface of the damping ring; (vi) the damping ring is adhesively adhered to the grooved protruding member on and/or at at least two surfaces of the damping ring and to the optical structure on and/or at at least a third surface of the damping ring; (vii) the damping ring is adhered, molded and/or bonded to at least one of the grooved protruding member and the optical structure using an adhesive or bonding material and/or element; (viii) the adhesive or bonding material and/or element operates to prevent slippage of the damping ring from the mount, thereby enhancing at least one of the dampening of the one or more stresses affecting the grooved protruding member and the tension, stretch, flex and/or compression effect of the damping ring; and (ix) the damping ring does not include the adhesive or bonding material and/or element.

The present invention and one or more components thereof are operable and adaptable to be used in conjunction with any suitable optical mount including, but not limited to, U.S. Pat. No. 8,092,030, issued on Jan. 10, 2012, having the same assignee as the present application, which is incorporated by reference herein in its entirety.

The present invention and one or more components thereof also may be used in conjunction with any suitable optical assembly including, but not limited to, optical assembly structures, interferometers, and/or retroreflectors such as those disclosed in U.S. Pat. Nos. 5,335,111; 5,949,543; 6,141,101; 6,473,185; 6,729,735; 6,752,503; 6,786,608; 6,827,455; 6,945,661; 7,168,817; 7,995,208; 8,092,030; 8,454,176; 8,567,968 to Bleier; U.S. Pat. No. 7,268,960 to Vishnia; U.S. Pat. Nos. 8,120,853; 8,205,852 and 8,205,853 to Jacobson et al.; and U.S. application Ser. No. 13/682,801, filed on Nov. 21, 2012, U.S. application Ser. No. 13/682,857, filed on Nov. 21, 2012, (presently pending), U.S. application Ser. No. 13/682,983, filed on Nov. 21, 2012, (presently pending), U.S. application Ser. No. 13/348,723, filed on Jan. 12, 2012, (presently pending), U.S. application Ser. No. 13/560,510, filed on Jul. 27, 2012, (presently pending), U.S. application Ser. No. 13/560,583, filed on Jul. 27, 2012, (presently pending), U.S. application Ser. No. 13/036,506, filed on Feb. 28, 2011, (presently pending), U.S. application Ser. No. 13/777,267, filed on Feb. 26, 2013 (presently pending), and U.S. application Ser. No. 13/965,333, filed on Aug. 13, 2013 (presently pending), each of which patents and applications are incorporated by reference herein in their entireties. One construction for a hollow retroreflector is as disclosed in U.S. Pat. No. 3,663,084 to Morton S. Lipkins.

Accordingly, it is an object of the invention to provide an improved mount for an optical structure.

Another object of the invention is to provide an improved mount for an optical structure which causes minimal external stresses to the reflective surfaces of the optical structure.

Still another object of the invention is to provide an improved mount for an optical structure wherein the mount achieves reductions in movement of the optical structure in order to achieve higher-accuracy distance measurements.

Yet a further object of the invention is to provide an improved mount for an optical structure wherein the mounting of the mount and optical structure to a support structure is easy and secure.

It is even a further object of the invention to provide an improved method of mounting an optical structure using the improved mount.

Other objects of the invention will in part be obvious and will in part be apparent from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

For the purposes of illustrating the various aspects of the invention, wherein like numerals indicate like elements, there are shown in the drawings simplified forms that may be employed, it being understood, however, that the invention is not limited by or to the precise arrangements and instrumentalities shown. To assist those of ordinary skill in the relevant art in making and using the subject matter hereof, reference is made to the appended drawings and figures, wherein:

FIG. 1 is an exploded perspective view of a mount, optical structure and screw, made in accordance with at least one embodiment of the present invention;

FIG. 2 is a perspective view of the structures of FIG. 1 as joined together;

FIG. 3A is a cross-sectional view taken along line 3-3 of FIG. 1;

FIG. 3B is a cross-sectional view taken along line 3-3 of FIG. 1 of an alternative embodiment of a tightening mechanism and holes for same that may be used with the structures of FIG. 1 in accordance with one or more aspects of the present invention;

FIG. 3C is a cross-sectional view taken along line 3-3 of FIG. 1 of another alternative embodiment of a tightening mechanism and holes for same that may be used with the structures of FIG. 1 in accordance with one or more aspects of the present invention;

FIG. 4A is a side view of the mount 10 of FIG. 1 along with another structure having a threaded member extending therefrom in accordance with one or more embodiments of the present invention;

FIG. 4B is a side view of an alternative embodiment for a mount having a threaded member extending therefrom along with another structure having a threaded opening therethrough in accordance with one or more embodiments of the present invention;

FIG. 5 is a perspective view of a roof mirror having a pin extending therefrom in accordance with one or more embodiments of the present invention;

FIG. 6 is an exploded perspective view of an alternative embodiment of a mount, optical structure and screw, made in accordance with one or more embodiments of the present invention;

FIG. 7 is a perspective view of the structures of FIG. 6 as joined together;

FIG. 8 is a perspective view of yet a further embodiment of a mount, optical structure comprising an optical filter and screw, in accordance with one or more embodiments of the present invention;

FIG. 9 is an exploded perspective view of the structures of FIG. 8;

FIGS. 10A-10F are cross-sectional views taken along the diameter of various embodiments of the protruding member employing different geometrical shapes for the groove/relieved portion thereof in accordance with one or more embodiments of the present invention;

FIG. 11A is a perspective view of at least an additional aspect of the protruding member having a groove spaced away from the optical structure, where the optical structure is shown in an exploded view from the protruding member, and used in tandem with a mount having radial reliefs spaced around, and in communication with, a recess of the mount in accordance with one or more embodiments of the present invention;

FIG. 11B is a perspective view of at least an additional aspect of the protruding member having a groove spaced away from the optical structure, where the optical structure is shown in an exploded view from the protruding member, and having radial reliefs disposed around a bottom portion of the protruding member placed in recess of the mount in accordance with one or more embodiments of the present invention;

FIGS. 12A-12B are graphs illustrating the unexpected and critical reduction and/or elimination of various forces/stresses on the optical structure by the experiment performed to compare the torque, and mirror (or optical) distortion resulting therefrom, affecting an optical structure having a protruding member without a groove (also referred to as a “Solid Post”; data shown in FIG. 12A) with the torque, and mirror (or optical) distortion resulting therefrom, affecting an optical structure having a protruding member with a groove (also referred to as a “Relieved Post”; data shown in FIG. 12B);

FIG. 13 is a graph illustrating the unexpected and critical reduction and/or elimination of various forces/stresses on the optical structure by another experiment performed to compare the torque, and mirror (or optical) distortion resulting therefrom, affecting an optical structure having a protruding member without a groove (also referred to as a “Solid Post”; data shown in curve 1300 of FIG. 13) with the torque, and mirror (or optical) distortion resulting therefrom, affecting an optical structure having a protruding member with a groove spaced away from the optical structure (also referred to as a “Relieved Post”; data shown in curve 1310 of FIG. 13);

FIG. 14 is a perspective view of at least one embodiment of an interferometer having a grooved protruding member with a damping ring disposed in or on the groove for use with a mount in accordance with at least one aspect of the present invention;

FIG. 15 is a perspective view of at least one embodiment of a retroreflector having a grooved protruding member with a damping ring disposed in or on the groove for use with a mount in accordance with at least one aspect of the present invention; and

FIG. 16 is a diagrammatic view of at least one embodiment of a grooved protruding member having a damping ring adhered in, to or on the groove in accordance with at least one aspect of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An improved mount for, and method of mounting, an optical structure having a grooved/relieved protruding member with a damping ring are disclosed herein. The mount may have the grooved/relieved protruding member extending from a surface of the optical structure, a base element for mounting the mount to another structure and an upper element extending from the base element having a first opening extending therethrough for receipt therein of at least a portion of the grooved/relieved member. The first opening defines first and second arms, each of the arms comprising a head portion and each of the head portions ending at an end. A second opening in the upper element extends through one of the head portions and the end thereof in a direction toward the other head portion, while a third opening exists in the upper element through the end of the other head portion in an orientation substantially opposite to and in communication with the second opening so that a tightening mechanism may be received through the second opening and the third opening. Tightening of the tightening mechanism into the third opening causes the ends of the head portions to draw toward each other so that the first opening of the upper element tightens around the at least a portion of the grooved/relieved protruding member. With the grooved/relieved protruding member, the mount provides the aforementioned advantages of providing a “hard mount” with dimensional stability and a high degree of optical flatness while also substantially reducing and/or eliminating stresses/forces from affecting the connected optical structure.

Turning now to the details of the figures, FIG. 1 is an exploded perspective view of a mount in accordance with at least one aspect of the present invention. A mount for an optical structure made in accordance with the invention is generally designated at 10 (best seen in FIGS. 1-2). In the particular case of the figures of this application, the optical structure portrayed is that of a hollow retroreflector, which will hereinafter generally be designated in the figures at 20. It is of course to be understood that other optical structures are anticipated to be compatibly used with mount 10, including but not limited to, roof mirrors (see e.g., roof mirror 520 of FIG. 5), optical filters and/or individual refractive/reflective/mirror panels (see e.g., optical filter 820 of FIGS. 8-9), and/or solid retroreflectors (not shown).

Retroreflector 20 is preferably made of fused quartz/fused silica or fine annealed Pyrex (i.e., any type of borosilicate glass or glasses having a low coefficient of thermal expansion) or glass ceramics, while mount 10 is preferably made of a metal alloy having a very low coefficient of thermal expansion, such as INVAR (e.g., a nickel iron alloy having a low coefficient of thermal expansion) or aluminum.

Hollow retroreflector 20 is comprised of a first panel 30, a second panel 40, and a third panel 50. Each of the panels 30, 40 and 50 has a corresponding reflective surface 32, 42 and 52. The higher the degree of optical flatness achieved in surfaces 32, 42 and 52 will in part determine the accuracy of the corresponding panels 30, 40 and 50. Panels 30, 40 and 50 are disposed substantially at right angles to each other so that reflective surfaces 32, 42 and 52 are also disposed substantially at right angles to each other. Each of panels 30, 40 and 50 also has non-reflective, back surfaces 34, 44 and 54 which are opposite to reflective surfaces 32, 42 and 52.

As with all hollow retroreflectors, retroreflector 20 is designed to receive an incoming (incident) light ray (not shown) and reflect the light ray off of the reflective surfaces 32, 42 and 52 and out from retroreflector 20 along a path substantially parallel to the incident light ray. Of course, the incident light ray can initially strike any one of the reflective surfaces without bearing upon the accuracy of the parallelism of the reflected light ray. The accuracy tolerances for retroreflector 20 will almost always depend upon the function to be performed by retroreflector 20. If high degrees of accuracy, i.e., parallelism of the incident and reflected light rays, is a primary purpose of retroreflector 20, then high degrees of precision must be created and maintained with respect to the flatness of and perpendicularity of reflective surfaces 32, 42 and 52.

One construction for a hollow retroreflector is as disclosed in U.S. Pat. No. 3,663,084 to Morton S. Lipkins. If the construction shown in the '084 patent is used herein, then each of panels 30, 40 and 50 of hollow retroreflector 20 has at least first and second sides 36 and 38, 46 and 48 and 56 and 58, respectively. The first and second sides of each of the panels are substantially perpendicular to each other and to each of the other sides of the other panels. As is seen in the figures, particularly FIGS. 1-2, second side 48 of panel 40 is abutted against and adhered to reflective surface 32 of panel 30, second side 38 of panel 30 is abutted against and adhered to reflective surface 52 of panel 50, and second side 58 of panel 50 is abutted against and adhered to reflective surface 42 of panel 40. Accordingly, each of panels 30, 40 and 50 is simultaneously an abutting panel at second sides 38, 48 and 58, and an adjacent panel at first sides 36, 46 and 56.

Turning now to a discussion of mount 10, it is seen from the figures (best seen in FIGS. 1-2, 4A, and 6-7) that mount 10 has an upper element 60 and a base element 100.

As seen in the figures (best seen in FIGS. 1-2, 4A, and 6-7), base element 100 has extending therein an opening 110. Opening 110 preferably extends through a bottom surface 112 of base 100, but may be placed anywhere on base 100. Opening 110 is preferably threaded to receive a correspondingly threaded member (see e.g., threaded extending member 123 of FIG. 4A) extending from some type of support structure (see e.g., support structure 140 of FIG. 4A). However, it is also to be understood that instead of having opening 110, a base element 100 a having a bottom surface 112 a may have an outwardly extending member (see e.g., threaded extending member 123 a of FIG. 4B) which would in turn be received into a cooperating opening 110 a on a support structure (see e.g., support structure 140 a of FIG. 4B). In this instance also it is preferred that the extending member and support opening both be threaded to allow for a more secure connection between the two. Additionally, other mounting constructions are intended to be encompassed in the invention, such as the use of a clamp from the support structure to securely hold base element 100, 100 a, 100 b, other structural arrangements for the base element 100, 100 a, 100 b and the upper element 60, 60 a, 60 b (see e.g., FIGS. 8-9 further discussed below), as are other constructions.

Turning now to a discussion of upper element 60 of mount 10, it is seen in FIGS. 1-3 that in a preferred embodiment upper element 60 has an opening 62 extending therethrough. In the embodiment shown herein opening 62 is circular and such a circular opening is preferred, but not mandatory, it being anticipated by the invention herein that opening 62 may be any geometric shape. It is also seen that opening 62 of upper element 60 creates two arms 64 and 65, each having a respective head portion 67 and 69. Head portion 67 ends at end 70, while head portion 69 ends at end 72. Ends 70 and 72 do not touch and have a gap 68 extending therebetween. Through head 69 extends opening 74, through which screw/bolt/tightening mechanism 80 (also referred to as “element 80”) is received. Opening 74 extends completely through head 69 and end 72 of head 69. As is best shown in FIGS. 3A-3C, a corresponding and communicating opening 75 extends through end 70 of head 67, so that element 80 is able to be received therein. Assuming element 80 is threaded (along a predetermined length or portion of the element 80) and that at least opening 75 is also threaded, then as element 80 is tightened into opening 75, ends 70 and 72 are drawn together. As ends 70 and 72 draw together, opening 62 of element 60 becomes smaller; i.e., the diameter lessens, thereby creating a clamping force against protruding member 90 of panel 30, discussed in more detail below. It is also to be understood herein that some, or all of, opening 74 may be correspondingly threaded (as shown in FIGS. 3A and 3C) to receive element 80 (e.g., the element 80 may be threaded along the length thereof to engage the threads in the hole 75 but the hole 74 may not include threads as shown in FIG. 3B; the element 80 may be threaded at a portion thereof that extends into the opening 75 and may not include threads at a portion thereof that is disposed or rests in the opening 74 when the element 80 is completely tightened into the opening 74 such that the threaded portion of the element 80 operates to draw the ends 70 and 72 together as shown in FIG. 3C; etc.). Additionally or alternatively, a substantial portion of the holes 74, 75 may be threaded such that the element 80 may lock the ends 70 and 72 in a predetermined orientation to each other (best seen in FIG. 3A). Additionally, a mount, and method for constructing same, that is the subject of U.S. patent application Ser. No. 11/674,315, filed on Feb. 13, 2007, having the same assignee as the present application, which issued as U.S. Pat. No. 8,092,030, on Jan. 10, 2012, and which is incorporated by reference herein in its entirety, may be used with one or more embodiments of the mount, and methods for constructing same, as discussed herein.

To help secure element 80 within the opening in end 70, all of, or at least a portion of, opening 74 may also be correspondingly threaded (e.g., the threads in the opening 74 may direct the threaded portion of the element 80 towards, and into, the opening 75 to draw the ends 70 and 72 together as aforementioned). In the figures as shown, element 80 is a threaded bolt having an Alan wrench opening in its head for tightening and loosening element 80, as is known in the art. Other elements 80 are anticipated herein; such as, but not limited to, screws and/or bolts having Philips or flat head openings. Other manners of tightening the clamping force of opening 62 by bringing ends 70 and 72 together are also anticipated herein, the primary inventive concept being the mounting of mount 10 through opening 62 onto protruding member 90. As way of a further example, another embodiment of the invention may involve no element 80 and no gap 68 between ends 70 and 72. Instead, opening 62 may be continuous and sized so that a little adhesive applied between the outer surface 92 of protruding member 90 allows opening 62 to be adhered to surface 92. Tightening mechanism or element 80 may be made from any material known to one skilled in the art, including, but not limited to, glass, metals, metal alloys, polymers, one or more materials having a low coefficient of thermal expansion, etc.

Turning now to a more detailed discussion of member 90 (also referred to as “protruding member 90” or “pin 90”), panel 30 may be formed such that member 90 is an integrally extending part of panel 30 or member 90 may be a separate member that is bonded to back surface 34 of panel 30. In the preferred embodiment, bonding refers to fusing or adhering member 90 to back surface 34 of panel 30. As seen in the figures (best seen in FIGS. 1-2), member 90 is circular and/or disk-shaped in cross section to conform to opening 62 of mount 10. However, as has been previously discussed, if opening 62 takes a different shape, member 90 would take the same shape as that of opening 62. By way of example of at least one embodiment shown in FIGS. 1-2, the protruding member 90 may include a first surface 91 (e.g., on a first end of the protruding member 90) and a second surface 93 (e.g., on a second end of the protruding member 90). The protruding member 90 may include a third surface (e.g., the outer surface 92 of the protruding member) extending between the first and second surfaces 91, 93. The protruding member 90 may be substantially circular and/or disk-shaped in cross section to conform to the opening 62 of the mount 10 when the opening 62 of the mount 10 is circular and/or disk-shaped. Because the protruding member 90 preferably is sized and shaped to conform to the opening 62, one surface (e.g., such as the first surface 91) may be either integral with the panel 30 or bonded, fused and/or adhered to the back surface 34 of the panel. The one surface (e.g., such as the first surface 91) and/or the protruding member 90 may be sized and shaped such that the protruding member 90 extends through the hole 62 so that the tightening mechanism (such as, but not limited to, the screw/bolt/tightening mechanism 80) may draw the ends 70, 72 of the heads 67, 69 together such that the opening 62 may be at least one of substantially on, in connection with and contracted around the protruding member 90. In at least one embodiment, the protruding member 90 may be cylindrical. The first surface 91 of the protruding member 90 may comprise at least one of: a surface bonded, fused and/or adhered to the back surface 34 of the panel 30; the back surface 34 of the panel 30; a surface of the panel 30 when the member 90 is integrally formed with the panel 30; the top surface of a cylinder (e.g., when the protruding member 90 is cylindrical); and any other surface known to those skilled in the art to include the structural attributes of the first surface 91 discussed herein. The second surface 93 of the protruding member 90 may comprise at least one of: a surface on the opposite side of the protruding member 90 from the first surface 91; a surface in contact with the third surface (e.g., the outer surface 92) of the protruding member 90 and spaced away from the panel 30 and/or the back surface 34 of the panel 30; the bottom surface of a cylinder (e.g., when the protruding member 90 is cylindrical); a surface of the cylinder that is inserted into and/or disposed within the opening 62; a surface of the protruding member 90 that is aligned with or substantially aligned with a surface of the arms 64, 65 (e.g., the surface of the arms 64, 65 that is on the opposite side of the upper element 60 of the mount 10 away from the panel 30); and any other surface known to those skilled in the art to include the structural attributes of the second surface 93 discussed herein. In at least one embodiment where the protruding member 90 does not extend all the way through the opening 62 or where the second surface 93 of the protruding member 90 is aligned with or substantially aligned with a surface of the arms 64, 65 (see e.g., FIG. 2), the opening 62 may be disposed at least one of substantially on, in connection with and around at least one of a third surface (e.g., the outer surface 92 of the protruding member 90) and the second surface 93. Any of the first, second and third surfaces 91, 93, 92 of the protruding member 90 may be solid (see e.g., FIGS. 1-2). For example, when the protruding member 90 is cylindrical, the first, second and third surfaces 91, 93, 92 of the protruding member 90 may define a solid cylinder. The first and second surfaces 91, 93 of the protruding member 90 may be substantially parallel or parallel to each other.

The method of mounting optical structure 20 onto mount 10 is to form an optical structure having a reflective surface and a protruding member extending from a back surface of the optical structure, wherein the protruding member is either integrally formed from, or bonded to, the back surface of the optical structure. Forming a mounting member having a base element having a construction for allowing the mounting member to be mounted to another structure, the mounting member further having an upper element having a first opening extending therethrough, such first opening forming two arms each having a head portion and ending at ends thereof such that the ends are preferably separated by a gap therebetween at least when the mounting member is not attached to the optical structure. Sliding the first opening of the mounting member over the protruding member of the optical structure. Tightening the first opening of the mounting member around the protruding member by inserting a tightening mechanism into a second opening located through one of the head portions of the mounting member and by further inserting and tightening the tightening member into a third opening in the other head portion of the mounting member so that the tightening member draws the two ends of the head portions together thereby contracting the first opening of the mounting member around the protruding member of the optical structure. The tightening member preferably being a threaded bolt which is received into the third opening and the third opening also being threaded. As previously stated above, the second opening of the mounting member may also be threaded in whole or in part along its length.

The manner of mounting described herein is an improvement over prior mounting manners and is equally good, if not better, at preventing distortion of reflective surface 32 (and therefore of reflective surfaces 42 and 52) so as to help maintain reflective surfaces 32, 42 and 52 in their substantially flat and substantially perpendicular relationship to each other. In particular, with the manner of mounting described herein there are no distortional stresses applied on reflective surface 32 by either the securing forces exerted by the contracting of first opening 62 around protruding member 90 or due to contraction or expansion of the mounting member due to temperature change, or other reasons. For example, as best seen in FIGS. 1-2, the upper element 60 and/or the opening 62 of the upper element 60 may be disposed at least one of substantially on, in connection with and around at least one of the third surface (e.g., the outer surface 92) of the protruding member 90 and the second surface 93. In particular, due to the orientation of protruding member 90 to reflective surface 32 and further since any such contracting or distortional forces exerted on member 90 from the mounting member are applied in directions/planes that are parallel to reflective surface 32, and not perpendicular to it, such forces will only nominally, if at all, affect the optical flatness of surface 32.

It will also be seen that the manner of mounting described herein achieves substantial rigidity between optical structure 20 and mount 10. Further, as described in the immediate above paragraph, the preferred low coefficient of thermal expansion metal alloy material which makes up mount 10 significantly reduces the effects of thermal expansion/contraction of mount 10 so as to substantially minimize these effects on the accuracy of optical structure 20.

In accordance with at least another aspect of the present invention, a critical, structural improvement to the aforementioned protruding member 90 structure has been unexpectedly achieved by the modification of the member 90 to include a relief or groove to further dissipate pressure on any connected optical structure and to more optimally maintain dimensional stability of the optical structure, protruding member and mount assembly. As illustrated in FIGS. 6-7, the modified pin or protruding member 90 a having an outer surface 92 a includes a relief or groove 94 a such that a top surface 97 a (also referred to as a first portion 97 a while the phrase “a first portion 97 a” may refer to another portion, or a portion including the top surface 97 a of member 90 a, e.g., the portion of member 90 a that is located above the second portion 96 a discussed below) of the member 90 a that operates to be connected (e.g., via fusing, adhering, bonding, etc.) to an optical structure, such as retroreflector 20, may be smaller than a lateral cross-section, such as bottom surface 98 a, of a base portion 96 a (also referred to as a second portion 96 a) of the member 90 a that operates to be located, and locked/tightened, within opening 62 of the mount 10. The first portion 97 a may, alternatively, be substantially the same size as or larger than the second portion 96 a. Preferably, the groove 94 a extends laterally along the protruding member 90 a and defines the first portion 97 a and the second portion 96 a on each side of the groove 94 a. While bonding may be used, permanently fusing the pin 90, 90 a having the groove 94 a to the bottom of the optical structure 20 provides the advantage of eliminating the need for use of a bonding technique and, thus, enables a much more stable and durable mounting method for achieving a “hard mount” with dimensional stability and/or maintaining a provided degree of optical flatness or a high degree of optical flatness.

There are various ways for the top surface 97 a to be “smaller” than the lateral cross-section, such as the bottom surface 98 a, (e.g., may be done in such a way that the structural integrity of the protruding member 90, 90 a is preserved) including, but not limited to, the top surface 97 a having a smaller surface area than the lateral cross-section, such as the bottom surface 98 a, the top surface 97 a having a smaller diameter than the lateral cross-section, such as the bottom surface 98 a, etc. Preferably, the diameter and/or the surface area of the top surface 97 a is substantially smaller than the diameter and/or the surface area of the lateral cross-section, such as the bottom surface 98 a, such that the diameter of the top surface 97 a is equal to or lesser than about the diameter of the lateral cross-section, such as the bottom surface 98 a, minus ten percent (10%). The groove 94 a may be various sizes. Preferably, the groove 94 a does not extend more than about 10% of the optical component size, or does not extend more than about 15% of the optical component size. For example, the groove 94 a may be about 50,000ths of an inch from a perimeter of the base portion of the protruding member 90, 90 a (e.g., the depth of the groove may be: (i) about 5% to about 15% from the outer diameter of the protruding member 90, 90 a (ii) about 10% to about 15% from the outer diameter of the protruding member 90, 90 a; etc.). For example, a 2 inch diameter post 90, 90 a may have a groove 94 a that is about 200,000ths to about 250,000ths of an inch from the outer diameter of the protruding member 90, 90 a. Additionally or alternatively, the groove 94 may be spaced at least one of: about 50,000ths of an inch from the optical structure 20; about 200,000ths to about 250,000ths of an inch from the optical structure 20; about 200,000ths of an inch from the optical structure; about 250,000ths of an inch from the optical structure 20; and about 50,000ths of an inch to about 250,000ths of an inch from the optical structure 20. Preferably, an optical beam that enters the optical structure, such as retroreflector 20, is not larger than 3″ clear aperture. However, the optical beam may be larger than 3″ clear aperture in at least another embodiment. The groove 94 a and/or the member 90, 90 a may be created by any method known to one skilled in the art, including, but not limited to, grinding, etching, laser etching, cutting, etc.

Preferably, in at least one embodiment of the present invention, the groove 94 a of the protruding member 90 a elevates and/or spaces any optical structure, such as the retroreflector 20, connected thereto away from the base portion 96 a of the member 90 a and/or the mount 10 because the groove 94 a may comprise space in between the optical structure and at least one of: (i) the base portion 96 a of the member 90 a and (ii) the mount 10. The groove 94 a may space the optical structure 20 away from the base portion 96 a and/or the mount 10 such that the optical structure, e.g., the retroreflector 20, does not directly contact a portion or surface of at least one of: the mount 10, the base portion 96 a of the member 90 a, the upper element 60 of the mount 10 and the base element 100 of the mount 10. Such structure is constructed to, and operates to: (i) concentrate any stress or force from the mount 10 onto the member 90 a rather than directly onto the optical structure 20; and (ii) reduce/dissipate and/or eliminate any resulting stress or force from distorting, or otherwise affecting, the optical structure 20. When the mount is assembled such that the top surface 97 a of member 90 a is connected/fused to the optical structure 20 and the base portion 96 a of the member 90 a is tightened/clamped within the upper element 60 of the mount 10, various types of stresses affect the assembly, including, but not limited to, tightening/clamping stress in between arms 64 and 65 of the mount 10, stress from rotation/tightening of the element 80 within mount 10, etc. However, because the member 90 a includes groove 94 a, such stresses that would otherwise be affecting the optical structure 20 more greatly are instead surprisingly and significantly dissipated/reduced and/or eliminated.

The aforementioned unexpected and critical reduction and/or elimination of various forces/stresses on the optical structure is evidenced by the experiment performed to compare the torque, and mirror (or optical) distortion resulting therefrom, affecting an optical structure having a protruding member without a groove (also referred to as a “Solid Post”) (e.g., as shown in FIG. 1) with the torque, and mirror (or optical) distortion resulting therefrom, affecting an optical structure having a protruding member with a groove (also referred to as a “Relieved Post”) (e.g., as shown in FIG. 6). The results of the experiment are illustrated in FIGS. 12A (i.e., “Solid Post” data) and 12B (i.e., “Relieved Post” data). As shown in FIG. 12A for the “Solid Post”, the mirror distortion (“P-V” or “peak-to-valley”; also referred to as k) at a wavelength of 633 nanometers (“nm”) ranged from about 0.2 P-V at a torque near zero ounce-force-inch (or “ozf-in”) (see data point 1201 on curve 1200 in FIG. 12A) to about 2.75 P-V at a torque greater than 80 ounce-force-inch (see data point 1203 on curve 1200 in FIG. 12A). At a torque value of about 32 to about 34 ounce-force-inch (e.g., about middle of the range measured; see data point 1202 on curve 1200 in FIG. 12A), the mirror distortion was measured at about 1.25 P-V.

In contrast, as shown in FIG. 12B for the “Relieved Post”, the mirror distortion (“P-V” or “peak-to-valley”) at a wavelength of 633 nanometers (“nm”) ranged from about 0.2 P-V at a torque near zero ounce-force-inch (or “ozf-in”) (see data point 1211 on curve 1210 in FIG. 12B) to about 0.25 P-V at a torque greater than 80 ounce-force-inch (see data point 1213 on curve 1210 in FIG. 12B). At a torque value of about 32 to about 34 ounce-force-inch (e.g., middle of the range measured; see data point 1212 on curve 1210 in FIG. 12B), the mirror distortion was measured at about 0.225 P-V.

The mount used for the “Solid Post” experiment (e.g., data shown in FIG. 12A) is substantially similar or identical to, and is, therefore, representative of the mount depicted in FIG. 1 or variations thereof in accordance with one or more aspects of the present invention. Similarly, the mount used for the “Relieved Post” experiment (e.g., data shown in FIG. 12B) is substantially similar or identical to, and is, therefore, representative of the mount depicted in FIG. 6 or variations thereof in accordance with one or more aspects of the present invention. Indeed, the results of the “Solid Post” and “Relieved Post” experiment (e.g., as shown in FIGS. 12A and 12B, respectively) are representative of various embodiments in accordance with one or more aspects of the present invention. While the experiment was performed at a wavelength of 633 nm, it is important to note that if the experiment was repeated at a different wavelength, the experimental data from that additional experiment would indicate the same relationship or correlation between torque and mirror distortion. Thus, these results: (i) illustrate practical conditions; (ii) are representative of general conditions for such optical structure mount assemblies; and (iii) also indicate that the addition of the groove is unique and achieves critical results/advantages, thereby supporting the groove modification as being novel and nonobvious.

The experimental data clearly indicates the critical improvement of employing a protruding member (or post) having a groove (or relief) instead of a protruding member (or post) without a groove (or relief). For example, when comparing the mirror distortions that occurred at the two torque values of about 32-34 ozf-in (i.e., about 1.25 P-V for Solid Post and about 0.225 P-V for Relieved Post; see data point 1202 in FIG. 12A and data point 1212 in FIG. 12B, respectively) and greater than 80 ozf-in (i.e., about 2.75 P-V for Solid Post and about 0.25 P-V; see data point 1203 in FIG. 12A and data point 1213 in FIG. 12B, respectively), the Solid Post assembly exhibited mirror distortions that were 555.55% greater and 1100% greater, respectively, than the mirror distortions of the Relieved Post assembly. Such results were quite surprising and greater than any expected reduction in mirror distortions due to the addition of the groove or relief, such as groove 94 a. Specifically, it is quite surprising that the distortion for the Relieved Post is consistently and minimally/barely increasing from about 0.2 P-V (e.g., at data point 1211 in FIG. 12B) to about 0.25 P-V (e.g., at data point 1213 in FIG. 12B) across the entire range of torque applied whereas the distortion for the Solid Post discussed above is much more erratic and increases greatly from about 0.2 P-V (e.g., at data point 1201 in FIG. 12A) to about 2.75 P-V (e.g., at data point 1203 in FIG. 12A) across the same range of torque applied. Indeed, the results are of a significant statistical and practical advantage because by making the subject structural change (i.e., by adding a groove or relief 94 a to the protruding member or post 90 as shown in member 90 a of FIGS. 6-7), which is an inexpensive and unique modification, the stresses/forces affecting a connected optical structure are significantly reduced. Not only are the results quite critical and significant statistically, thereby evidencing nonobviousness, but making such a modification is also unique and nonobvious because those skilled in the art would be deterred from making the subject modification. Specifically, those skilled in the art would be concerned with improving stability and stiffness of the optical mount assembly, and would, therefore, avoid compromising the structural integrity of the protruding member, the optical structure, the mount and/or the overall assembly by adding a groove, such as groove 94 a. Thus, making such a groove proceeds contrary to accepted wisdom in the field of optics, and further supports the unique, nonobvious nature of one or more aspects of the present invention.

Additionally, the use of the groove/relief 94 a provides an assembly for achieving dimensional stability and permits the hard mounts to maintain any provided degree of flatness (e.g., less than about λ/4; at least about λ/4, at least about λ/10, between about λ/4 and about λ/30, greater than λ/30, etc.) and more particularly, to maintain a high degree of flatness (e.g., at least about λ/20, at least about λ/15, between about λ/15 and about λ/20, between about λ/15 and about λ/30, etc.) after the mount is constructed, especially when using any clamping forces, rotating forces (such as torque), etc.

In accordance with at least another embodiment of the present invention, the optical structure may comprise a mirror/reflective/refractive panel or an optical filter 820 having a protruding member 90 b as shown in FIGS. 8-9. The optical filter 820 may be a flat piece of glass, and the protruding member 90 b may have a groove 94 b and a top surface 97 b such that the bottom surface 824 of the optical filter 820 sits on top of the top surface 97 b. The optical filter 820 may be connected (e.g., via fusing, bonding, adhering, etc.) to the member 90 b, e.g., in similar fashion to optical structure 20 being connected to the member 90, 90 a as discussed above. As best seen in FIG. 9, the groove 94 b may be fashioned geometrically to stop at top surface 97 b and two extensions 81 a, 81 b may extend from the top surface 97 b of the member 90 b to define a recess 82 therebetween. The recess 82 permits the optical filter 820 to sit therein. Preferably, the optical filter 820 is sufficiently located in the recess 82 to be properly positioned and/or centered, e.g., in a centering mechanism, for the connection process to the member 90 b, e.g., via fusing, adhering, etc. The extensions 81 a, 81 b may be hemispherical in geometry (as shown in FIGS. 8-9), or may be any other geometry to maintain the principles and aspects of the present invention discussed herein. Preferably, the extensions 81 a, 81 b are sized and shaped such that they do not increase the surface area and/or the diameter of the top surface 97 b that would exist if such extensions 81 a, 81 b were not used. For example, a surface area and/or diameter of the combined areas of the top surface 83 a of the extension 81 a, the top surface 83 b of the extension 81 b and the top surface 97 b of the member 90 b (i.e., the base of recess 82) that is shown in FIG. 9 may be substantially the same or smaller than a surface area and/or diameter of the top surface 97 b that would exist without the use of the extensions 81 a, 81 b (e.g., if the extensions 81 a, 81 b were removed or not used, the top surface 97 b may extend to the groove 94 b substantially all along the perimeter of the groove 94 b). The extensions 81 a, 81 b may be made of substantially similar material to that of member 90 b and may be connected such that the extensions become integral thereto (e.g., via fusing). Also, the extensions 81, 81 b may be adhered to, connected to or fused to the member 90 b without being integral thereto. Alternatively, as similarly discussed above for the members 90, 90 a, the member 90 b and/or the groove 94 b thereof may be created by any method known to one skilled in the art, including, but not limited to, grinding, etching, laser etching, cutting, etc. In at least one embodiment, the member 90 b may be created, e.g., via etching, grinding, cutting, etc., such that the groove 94 b and the extensions 81 a, 81 b are already integral thereto (e.g., the groove 94 b and the extensions 81 a, 81 b may be etched from a large piece that is sized and shaped to form the member 90 b).

The member 90 b may be connected (e.g., via clamping, tightening, etc.) to a mount 10 b, e.g., in similar fashion to member 90, 90 a being connected to mount 10, 10 a as discussed above. Indeed, those skilled in the art will appreciate that the elements (e.g., upper element 60 b; opening 62 b; arms 64 b, 65 b; head portions 67 b, 69 b; ends 70 b, 72 b of head portions 67 b, 69 b; opening 74 b; base element 100 b; opening 110 b in the base element 100 b; etc.) of the mount 10 b may operate in similar fashion to those like-numbered elements (e.g., substantially same numbers but with a letter such as 10 and 10 a, 96 and 296 discussed below, etc.) of mounts 10, 10 a as discussed above or any additional like-numbered elements discussed further herein below. For example, a tightening mechanism 80 b (which may operate in a similar fashion as tightening mechanism 80) may be screwed into aperture 74 b such that ends 70 b, 72 b of heads 67 b, 69 b of arms 64 b, 65 b, respectively, are drawn together around at least a portion, e.g., base portion 96 b, of the member 90 b when the member 90 b is placed into opening 62 b of upper element 60 b of the mount 10 b.

Additionally, the mount 10 b may be connected to another structure (e.g., another structure 140 as shown in FIG. 4A, another structure 140 a as shown in FIG. 4B, etc.) via an element (e.g., a pin; an extending member, such as the extending member 123 of FIG. 4A or the extending member 123 a of FIG. 4B; etc.) extending through the opening 110 b or opening 115 of the base element 100 b. Additionally or alternatively, the mount 10 b may include a base element 100 b extending from the upper element 60 b and having a relatively smaller volume than the volume of the upper element 60 b such that the base element may be easily connected, e.g. via clamping, compressing, etc. to another structure. Such a structure may lessen the force/stress on the optical filter glass 820 because any clamping, compressing, etc. of the base element 100 b is limited by the reduced/smaller volume of the base element 100 b. The base element 100 b and the upper element 60 b may be connected such that the base element 100 b and the upper element 60 b are substantially co-linear and/or co-planar (e.g., the base element 100 b extends from the upper element 60 b at substantially an angle of about 180 degrees). Additionally or alternatively, the base element 100 b may include any geometric shape, e.g., the surfaces are chamfered, sloped, tapered, etc., such that the surface of the base element 100 b that is ultimately clamped or otherwise connected to another structure is reduced. Alternatively, the base element 100 b and the upper element 60 b may be connected at an angle in similar fashion to the upper element 60, 60 a and the base element 100, 100 a as discussed above and shown in FIGS. 1-2 and 4A-4B.

In accordance with at least one embodiment of the present invention, the groove/relief 94 a, 94 b of the protruding member 90 a, 90 b may be any geometric shape, including, but not limited to, circular, ovular, rectangular, square-shaped, etc., and may include slopes, chamfered surfaces, tapers, etc. For example, as shown in the embodiment of FIGS. 6-7, the embodiment of FIGS. 8-9 and FIG. 10A, the groove 94 a, 94 b may extend circularly around the perimeter of the member 90 a, 90 b and is formed at substantially a right angle such that the outer surface 92 a, 92 b of the member 90 a, 90 b extends inward (e.g., substantially parallel to the top 97 a, 97 b and bottom surfaces 98 a, 98 b of the member 90 a, 90 b) from the top of the base portion 96 a, 96 b and then extends vertically substantially at a right angle or perpendicular to the top surface 97 a, 97 b and bottom surface 98 a, 98 b of the member 90 a, 90 b.

Alternatively, as shown in FIGS. 10B-10E, a groove, such as grooves 94 a, 94 b of any protruding member, such as protruding members 90 a, 90 b, may employ different geometrical shapes for the groove/relieved portion thereof in accordance with one or more embodiments of the present invention. As such, while, for example, FIGS. 8-9 and FIG. 10A may employ the same or similar groove 94 b (or any other element thereof as indicated by like numerals), any of the geometrical shapes for the groove/relieved portion of any protruding member, such as the protruding members 90 a, 90 b, as shown in any of FIGS. 10A-10F may be used for any of the various embodiments of protruding members discussed herein. As shown in FIG. 10B, the groove 94 c is formed from a chamfered surface having a consistent slope extending from the base portion 96 c of the member 90 c to the top surface 97 c thereof. The groove 94 c may extend substantially around the perimeter of the member 90 c. As shown in FIG. 10C, the groove 94 d is formed from a chamfered surface having a changing convex slope extending from the base portion 96 d of the member 90 d to the top surface 97 d thereof. The groove 94 d may extend substantially around the perimeter of the member 90 d. Alternatively, as shown in FIG. 10D, the chamfered surface may have a concave slope extending from the base portion 96 e of member 90 e to the top surface 97 e thereof. The groove 94 e may extend substantially around the perimeter of the member 90 e. Additionally, as shown in FIG. 10E, the chamfered surface may have a concave slope extending from the base portion 96 f of member 90 f to the top surface 97 f thereof such that the surface area and/or diameter of the top surface 97 f may have substantially the same surface area and/or diameter of a lateral cross-section of the base portion 96 f. Several lateral cross-sections of the member 90 f that are located above the base portion 96 f may have a surface area and/or diameter that are smaller than the surface area and/or diameter of the lateral cross-section of the base portion 96 f Additionally, the volume of the portion of the member 90 f located above the base portion 96 f may be smaller than the volume of the base portion 96 f. The groove 94 f may extend substantially around the perimeter of the member 90 f While it is preferred that the geometry of the groove 94 a-f corresponds to the geometry of the member 90 a-f and the opening 62, 62 b (e.g., if the opening 62, 62 b and the member 90 a-f are circular, then the groove 94 a-f may be circular such that the groove 94 a-f extends circularly substantially around the perimeter of the member 90 a-e), it is not mandatory. For example, even if the opening 62, 62 b and the member 90 a-f are circular, the groove 94 a-f may be ovular, rectangular, form pillars on top of the base portion 96 a-f of the member 90 a-f (e.g., such that the top of the member 90 a-f resembles a “button” when viewed from above), etc.

Additionally or alternatively, as shown in FIG. 10F, a groove, such as groove 294 of any protruding member, such as protruding member 290, 290 a, 290 b, may be spaced away from the top surface 297 of the protruding member, and is, therefore, spaced away from any optical structure, such as optical structure 20 (e.g., the bottom surface 34 of the optical element 30 of the optical structure 20), that may be attached to the top surface 297 thereof. The groove 294 may employ different geometrical shapes for the groove/relieved portion thereof in accordance with one or more embodiments of the present invention. For example, as shown in the embodiments of FIGS. 11A and 11B (discussed further below) and in FIG. 10F, the groove 294 may extend circularly around the perimeter of the member 290, 290 a, 290 b and may be formed at substantially a right angle such that the outer surface 292 of the member 290, 290 a, 290 b extends inward (e.g., substantially parallel to the top 297 and bottom surface 298 of the member 290, 290 a, 290 b) from the top of the base portion 296, 296 a, 296 b and then extends vertically at substantially a right angle or perpendicular to the top surface 297 and bottom surface 298 of the member 290, 290 a, 290 b. Then, the outer surface 292 extends outwardly substantially parallel to the top surface 297 and the bottom surface 298. Once the outer surface has extended outwardly to the point where the diameter of the portion (e.g., top portion 211 as discussed further below with reference to FIGS. 11A-11B) of the member 290, 290 a, 290 b above the groove 294 is substantially equal to (although, alternatively, such an extension may occur where the diameter of the portion of the member 290, 290 a, 290 b is smaller than or larger than) the diameter of the bottom portion 296, 296 a, 296 b, then the surface 292 extends vertically for a predetermined distance at substantially a right angle or perpendicular to the top surface 297 and bottom surface 298. Once the surface 292 extends for the predetermined distance, the surface extends inward again such that the surface 292 defines the top surface 297 of the member 290, 290 a, 290 b. Preferably, the top surface 297 is substantially parallel to the bottom surface 298 of the member 290, 290 a, 290 b. This structure provides, and defines, a portion (e.g., top portion 211 as discussed further below with reference to FIGS. 11A-11B) of the member 290, 290 a, 290 b that is located above the groove 294 where that portion may be smaller than (as shown in FIG. 10F), substantially equal to, or larger than the bottom portion 296, 296 a, 296 b. Alternatively, the groove 294 of the member 290, 290 a, 290 b may have a chamfered or concave slope as similarly shown for the groove 94 c-94 f in FIGS. 10B-10E. Preferably, the top surface 297 has a surface area and/or diameter that is substantially the same as the surface area and/or diameter of a lateral cross-section of the base portion 296, 296 a, 296 b or of the bottom surface 298 of the member 290, 290 a, 290 b. Preferably, one or more lateral cross-sections of the portion (e.g., top portion 211 as shown in FIGS. 11A-11B) of the member 290, 290 a, 290 b located between the groove 294 and the top surface 297 have a surface area and/or diameter that is substantially the same as the surface area and/or diameter of a lateral cross-section of the base portion 296, 296 a, 296 b or of the bottom surface 298 of the member 290, 290 a, 290 b. Preferably, the volume of the portion (e.g., top portion 211 as shown in FIGS. 11A-11B) of the member 290, 290 a, 290 b located between the groove 294 and the top surface 297 has a volume that is smaller than the volume of the bottom portion 296, 296 a, 296 b. Additionally or alternatively, the surface area (of the entire portion, such as the top portion 211, or of one or more lateral cross-sections of the portion, such as the top portion 211), the diameter and/or the volume of the portion of the member 290, 290 a, 290 b located between the groove 294 and the top surface 297 may be smaller than, equal to or larger than the surface area (of the entire bottom portion 296, 296 a, 296 b or of one or more lateral cross-sections of the bottom portion 296, 296 a, 296 b), the diameter and/or the volume of the bottom portion 296, 296 a, 296 b of the member 290, 290 a, 290 b.

While it is preferred that the geometry of the groove 294 corresponds to the geometry of the member 290, 290 a, 290 b and the opening 62, 62 b, 62 c, 62 d (e.g., if the opening 62, 62 b, 62 c, 62 d and the member 290, 290 a, 290 b are circular, then the groove 294 may be circular such that the groove 294 extends circularly substantially around the perimeter of the member 290, 290 a, 290 b), it is not mandatory. For example, even if the opening 62, 62 b, 62 c, 62 d and the member 290, 290 a, 290 b are circular, the groove 294 may be ovular, rectangular, form pillars on top of the base portion 296, 296 a, 296 b of the member 290, 290 a, 290 b (e.g., such that the top of the member 290, 290 a, 290 b resembles a “button” when viewed from above), etc.

In accordance with at least another embodiment of the present invention, a groove, such as groove 294 or groove 94 a-94 f, of a protruding member 290, 290 a, 290 b may be shifted or spaced away from an optical structure, such as the optical structure 20, connected to the protruding member 290, 290 a, 290 b as shown in FIGS. 10 and 11A-11B. By shifting away (or spacing away) the groove 294 from the optical structure 20 (e.g., the groove 294 may be disposed at a location along the protruding member 290, 290 a, 290 b that is at a predetermined distance from a surface of the protruding member 290, 290 a, 290 b that is in contact with the optical structure, such as optical structure 20), any pressure or stresses (e.g., sheer forces, rotational forces, compression forces, etc.) that would normally pass through the protruding member 290, 290 a, 290 b and to the optical structure 20 (e.g., when a post or protruding member does not include a groove) are instead substantially concentrated and/or localized at the groove 294, thereby substantially reducing and/or eliminating such pressure or stresses from affecting the optical structure 20. The location where the pressure or stresses are localized (e.g., at groove 294) may be located further away from the optical structure 20 (e.g., as compared to an assembly having a groove closer to the optical structure, such as, but not limited to, the assembly of FIGS. 6-7, the assembly of FIGS. 8-9, etc.). Preferably, when the groove 294 is spaced away from the optical structure 20 (e.g., the groove is located substantially near or in the middle of the protruding member 290, 290 a, 290 b; the groove 294 may be disposed at a location along the protruding member 290, 290 a, 290 b that is at a predetermined distance from a surface of the protruding member 290, 290 a, 290 b that is in contact with the optical structure 20; the groove 294 is located towards the mount 210 a, 210 b rather than towards the optical structure 20; the groove 294 is not directly adjacent to the optical structure 20; the groove is located towards the optical structure 20 rather than towards the mount 210 a, 210 b; etc.), the groove 294 defines a first portion 211 (also referred to as “a top portion 211”) that connects to the optical structure 20 and a second portion 296, 296 a, 296 b (also referred to as “a bottom portion 296, 296 a, 296 b”) that is disposed within a recess 62 c, 62 d of the mount 210 a, 210 b as best seen in FIGS. 11A-11B. Preferably, the groove 294 extends laterally along the protruding member 290, 290 a, 290 b and defines the first portion 211 and the second portion 296, 296 a, 296 b on each side of the groove 294. The first portion 211 may be sized and shaped to be smaller, substantially the same size and/or larger than the second portion 296, 296 a, 296 b. Regardless of the size and shape of the first portion 211 to the second portion 296, 296 a, 296 b, the groove 294 operates to substantially reduce and/or eliminate pressure or stresses affecting the optical structure 20.

The groove 294 may be formed (e.g., sized and shaped) and may operate to achieve the advantages, surprising results, and unique, nonobvious properties as similarly explained above with respect to the grooves 94 a-94 f (as shown in FIGS. 10A-10E). For example, the groove 294 may operate to: (i) concentrate any stress or force from the mount 210 a, 210 b onto the member 290, 290 a, 290 b rather than directly onto the optical structure 20; (ii) reduce/dissipate and/or eliminate any resulting stress or force from distorting, or otherwise affecting, the optical structure 20; and may preserve and/or maintain the provided flatness, such as, but not limited to, a high degree of flatness as discussed herein. When the mount is assembled such that the top portion 211 of the member 290, 290 a, 290 b is connected/fused to the optical structure 20 (e.g., connected/fused to the bottom surface 34 of the optical element 30 of the optical structure 20) and the base portion 296, 296 a, 296 b of the member 290, 290 a, 290 b is tightened/clamped within the recess 62 c, 62 d of the mount 210 a, 210 b, various types of stresses affect the assembly, including, but not limited to, tightening/clamping stress in the mount 210 a, 210 b, stress from rotation/tightening of the element 80 within mount 210 a, 210 b, etc. However, because the member 290, 290 a, 290 b includes the groove 294, such stresses that would otherwise be affecting the optical structure 20 more greatly are instead surprisingly and significantly dissipated/reduced and/or eliminated.

The aforementioned unexpected and critical reduction and/or elimination of various forces/stresses on the optical structure is evidenced by the additional experiment performed to compare the torque, and mirror (or optical) distortion resulting therefrom, affecting an optical structure having a protruding member without a groove (also referred to as a “Solid Post”) (e.g., similar to the structure as shown in FIG. 1) with the torque, and mirror (or optical) distortion resulting therefrom, affecting an optical structure having a protruding member with a groove spaced away from an optical structure (also referred to as a “Relieved Post”) (e.g., as shown in FIG. 11A but with the optical structure 20 (e.g., the bottom surface 34 of the optical element 30 of the optical structure 20) connected to the top surface 297 of the protruding member 290 a, FIG. 11B but with the optical structure 20 (e.g., the bottom surface 34 of the optical element 30 of the optical structure 20) connected to the top surface 297 of the protruding member 290 b, FIG. 11A but with the optical structure 20 (e.g., the bottom surface 34 of the optical element 30 of the optical structure 20) connected to the top surface 297 of the protruding member 290 a and without the reliefs 220 a, FIG. 11B but with the optical structure 20 (e.g., the bottom surface 34 of the optical element 30 of the optical structure 20) connected to the top surface 297 of the protruding member 290 b and without the reliefs 220 b, etc.). The results of the experiment are illustrated in FIG. 13 and in the table as follows:

Solid Relieved in-oz Post Post Torque PV PV 0 0.294 0.142 16 0.286 0.144 24 0.541 0.162 32 0.832 0.159 40 1.005 0.177 48 1.162 0.168 60 1.53 0.16 80 1.859 0.198 100 2.361 0.2

As shown from the “Solid Post” curve 1300 in FIG. 13, the mirror distortion (“P-V” or “peak-to-valley”) ranged from about 0.294 P-V at a torque of zero inch-ounces (or “in-oz”) (see data point 1301 on curve 1300 in FIG. 13) to about 2.361 P-V at a torque of 100 inch-ounces (see data point 1303 on curve 1300 in FIG. 13). At a torque value of 48 inch-ounces (e.g., about middle of the range measured), the mirror distortion was measured at 1.162 P-V (see data point 1302 on curve 1300 in FIG. 13).

In contrast, as shown from the “Relieved Post” curve 1310 in FIG. 13, the mirror distortion (“P-V” or “peak-to-valley”) ranged from about 0.142 P-V at a torque of zero inch-ounces (or “in-oz”) (see data point 1311 on curve 1310 in FIG. 13) to about 0.2 P-V at a torque of 100 inch-ounces (see data point 1313 on curve 1310 in FIG. 13). At a torque value of 48 inch-ounces (e.g., middle of the range measured), the mirror distortion was measured at about 0.168 P-V (see data point 1312 on curve 1310 in FIG. 13).

The mount used for the “Solid Post” experiment (e.g., results of which are illustrated via curve 1300 in FIG. 13) is substantially similar or identical to, and is, therefore, representative of the mount depicted in FIG. 1 or variations thereof in accordance with one or more aspects of the present invention. Similarly, the mount used for the “Relieved Post” experiment (e.g., results of which are illustrated via curve 1310 in FIG. 13) is substantially similar or identical to, and is, therefore, representative of the mount(s) depicted in FIG. 11A, FIG. 11B or variations thereof (e.g., as shown in FIGS. 11A-11B but with the optical structure 20 (e.g., the bottom surface 34 of the optical element 30 of the optical structure 20) connected to the top surface 297 of the protruding member 290 a, 290 b and without the reliefs 220 a, 220 b) in accordance with one or more aspects of the present invention. Indeed, the results of the “Solid Post” and “Relieved Post” experiment (e.g., as illustrated via curves 1300 and 1310, respectively, in FIG. 13) are representative of various embodiments in accordance with one or more aspects of the present invention. Thus, these results: (i) illustrate practical conditions; (ii) are representative general conditions when dealing with such optics; and (iii) also indicate that the addition of the groove is unique, achieves critical results/advantages, thereby supporting the groove modification as being novel and nonobvious.

The experimental data clearly indicates the critical improvement of employing a protruding member (or post) having a groove (or relief) spaced away from an optical structure instead of a protruding member (or post) without a groove (or relief). For example, when comparing the mirror distortions that occurred at the two torque values of 48 inch-ounces (i.e., about 1.162 P-V for Solid Post and about 0.168 P-V for Relieved Post with spaced away groove; see data point 1302 of curve 1300 in FIG. 13 and data point 1312 of curve 1310 in FIG. 13, respectively) and 100 in-oz (i.e., about 2.361 P-V for Solid Post and about 0.2 P-V for Relieved Post with spaced away groove; see data point 1303 of curve 1300 in FIG. 13 and data point 1313 of curve 1310 in FIG. 13, respectively), the Solid Post assembly exhibited mirror distortions that were about 692% greater and 1180.5% greater, respectively, than the mirror distortions of the Relieved Post assembly with the spaced away groove. Such results were quite surprising and greater than any expected reduction in mirror distortions due to the addition of the groove, where the groove was spaced away from the optical structure 20. Specifically, it is quite surprising that the distortion for the Relieved Post is consistently and minimally/barely increasing from about 0.142 P-V to about 0.2 P-V (see curve 1310 in FIG. 13) across the entire range of torque applied whereas the distortion for the Solid Post discussed above is much more erratic and increases greatly, especially beyond 16 inch-ounces and towards the higher end of the torque applied, from about 0.294 P-V to about 2.361 P-V (see curve 1300 in FIG. 13). Indeed, the results are of a significant statistical and practical advantage because by making the subject structural change (i.e., by adding a groove or relief 294 to the protruding member or post 290, 290 a, 290 b that is spaced away from the optical structure 20 as shown in FIG. 10 and FIGS. 11A-11B but with the optical structure 20 (e.g., the bottom surface 34 of the optical element 30 of the optical structure 20) connected to the top surface 297 of the protruding member 290 a, 290 b), which is an inexpensive and unique modification, the stresses/forces affecting a connected optical structure, such as optical structure 20, are significantly reduced. Not only are the results quite critical and significant statistically, thereby evidencing nonobviousness, but making such a modification is also unique and nonobvious because those skilled in the art would be deterred from making the subject modification. As explained above, those skilled in the art would be concerned with improving stability and stiffness of the optical mount assembly, and would, therefore, avoid compromising the structural integrity of the protruding member, the optical structure, the mount and/or the overall assembly by adding such a groove. Thus, making such a groove proceeds contrary to accepted wisdom in the field of optics, and further supports the unique, nonobvious nature of one or more aspects of the present invention.

In accordance with at least another embodiment of the present invention, one or more reliefs 220 a, 220 b (also referred to as notches or depressions 220 a, 220 b) may be disposed and/or formed in and/or on (e.g., in communication with, as part of, etc.) the perimeter of the recess 62 c of the mount 210 a (best seen in FIG. 11A) or may be formed on/in/around the perimeter (e.g., in communication with, as part of, etc.) of the bottom portion, such as bottom portion 296 b, of the protruding member, such as protruding member 290 b (best seen in FIG. 11B), thereby reducing physical contact, and, thus, the transfer of pressure or stresses/forces, between the mount 210 a, 210 b and the protruding member 290, 290 a, 290 b. Preferably, the one or more reliefs or notches comprise radial reliefs/notches 220 a, 220 b. Preferably, the reliefs/notches 220 a, 220 b are constructed (e.g., sized, shaped, etc.) in and/or on the protruding member 290 b and/or in and/or on the mount 210 a such that the reliefs/notches 220 a, 220 b permit the gaps 68 c, 68 d to function without interference (e.g., the gaps 68 c, 68 d may perform substantially similar or identical to gaps 68, 68 b as discussed above). The reliefs/notches 220 a, 220 b may be created by any method known to one skilled in the art, including, but not limited to, grinding, etching, laser etching, cutting, etc.

The member 290, 290 a, 290 b may be connected (e.g., via clamping, tightening, etc.) to a mount 210 a, 210 b, e.g., in similar fashion to member 90, 90 a, 90 b being connected to mount 10, 10 a, 10 b as discussed above. Indeed, those skilled in the art will appreciate that the elements (e.g., upper portion 211; bottom portion 296, 296 a, 296 b; groove 294; opening 62 c, 62 d; opening 212 a, 212 b of mount 210 a, 210 b; etc.) of the protruding member 290, 290 a, 290 b and/or mount 210 a, 210 b may operate in similar or identical fashion to those respective elements of the protruding members 90 a-90 f (such as, but not limited to upper surface 97 a-97 f; bottom portion 96 a-96 f; groove 94 a-94 f; etc.) and/or of the mounts 10, 10 a, 10 b (such as, but not limited to opening 62, 62 b; opening 74, 74 b; opening 110; etc.) as discussed above or any additional like-numbered elements discussed further herein below.

Additionally, the mount 210 a, 210 b may be connected to another structure as discussed above (e.g., another structure 140 as shown in FIG. 4A, another structure 140 a as shown in FIG. 4B, etc.) via an element (e.g., a pin; an extending member, such as the extending member 123 of FIG. 4A or the extending member 123 a of FIG. 4B; etc.) extending through the opening 212 a, 212 b of the mount 210 a, 210 b. Additionally or alternatively, the mount 210 a, 210 b may include a base element, such as base element 100 b shown in FIGS. 8-9, such that the base element may be easily connected, e.g. via clamping, compressing, etc. to another structure. Such structure may lessen the force/stress on the optical structure 20 attached to the mount 210 a, 210 b.

In general as described above, posts or protruding members (e.g., the protruding member 90) may be right circular cylinders, generally of greater diameter than height, that may be adhesive bonded or fused on one of the end caps or surfaces that faces to the assembly to which the protruding member (e.g., the protruding member 90) is mounting. An end-user may grip a post or protruding member (e.g., the protruding member 90) using a squeezing hoop-type or split clamp, thereby causing a large normal force between the clamp and the circular periphery of the post (e.g., the protruding member 90). Because the normal force is large, the frictional force in directions normal to the normal force, i.e., between post (e.g., the protruding member 90) and clamp, is very high. This mounts the optical component (e.g., the optical structure 20) containing the post (e.g., the protruding member 90) to another assembly to which the clamp is affixed in a stable fashion.

As described above, the novelty of using a protruding member (e.g., the protruding member 90) is so that the stress field (e.g., due to the squeezing of a clamp onto the post) does not transmit deleterious strain motions to the one or more optical surfaces of an optical structure (e.g., the optical structure 20). Put another way, the stress field “damps down” in distances sufficiently short that there is no strain field (displacement) effect at distances associated with the critical optical surfaces (e.g., of the optical structure 20), so such optical surfaces are unaffected.

Such general posts are not without problems. It was found by the inventors that in mounting an interferometer and a retroreflector by using one or more posts without grooves, that the inventors were still very limited in the amount of squeezing the inventors could do before the aforementioned strain field in fact did transmit to the optical surfaces. Sometimes, the allowable amount of squeezing and hence mounting frictional force, from a distortion point of view, were insufficient to stably mount the optical component under shock loading. Put another way, due to distortion, the inventors, in at least one embodiment of the post having no groove, were not able to squeeze the post as hard as the inventors would have liked for stable optical mounting, and at the light squeezes that did not affect optical surfaces, one or more embodiments of such a mounting using the posts or protruding members having no grooves may come apart under shock loading.

As discussed above, one improvement that alleviates the above problem is to put a groove (e.g., the groove 94 a, 94 b, 94 c, 94 d, 94 e, 94 f, 294, etc.) in the post (e.g., the grooved protruding members 90 a, 90 b, 90 c, 90 d, 90 e, 90 f, 290, 290 a, 290 b, etc.), thereby “necking it down” at or near the face of a protruding member that abuts the component (e.g., the optical structure 20) being mounted. In this way, moments associated with the post stress field are reduced. This reduces the deleterious strain field that could spoil the optical surfaces of the component (e.g., the optical structure) being mounted. Such a grooved arrangement is disclosed in U.S. patent application Ser. No. 13/036,506, filed on Feb. 28, 2011, and presently pending, the entirety of which patent application is incorporated by reference herein.

As a further surprise, it was found that one or more embodiments of the relief or groove 94 a, 94 b, 94 c, 94 d, 94 e, 94 f, 294, etc. of one or more of the grooved protruding members 90 a, 90 b, 90 c, 90 d, 90 e, 90 f, 290, 290 a, 290 b, etc. of one or more mounts (e.g., mount 10) as described herein may introduce a new problem. Specifically, because the grooved portion of the protruding member 90 a, 90 b, 90 c, 90 d, 90 e, 90 f, 290, 290 a, 290 b, etc. is now narrower than a protruding member, such as the protruding member 90 without a groove therein, the protruding member 90 a, 90 b, 90 c, 90 d, 90 e, 90 f, 290, 290 a, 290 b, etc. did not provide as stable a mounting for the optical structure 20 attached thereto, e.g., such as a retroreflector, interferometer, mirror panel, etc. Such a structural change of a protruding member (e.g., the protruding member 90 a, 90 b, 90 c, 90 d, 90 e, 90 f, 290, 290 a, 290 b, etc.) with a groove (e.g., the groove 94 a, 94 b, 94 c, 94 d, 94 e, 94 f, 294, etc.) is a reason as to the uniqueness and nonobviousness of such a feature. For example, in the case of a post-mounted monolithic Michelson interferometer employed as the active element in an FTIR spectrometer, the “necked-down” post (e.g., the grooved protruding member 90 a, 90 b, 90 c, 90 d, 90 e, 90 f, 290, 290 a, 290 b, etc.) caused the mounted interferometer to be more vibrationally sensitive. In particular, a “bowing at the waist” vibrational mode was observed, that in the operation of the aforementioned spectrometer, which caused the optical path difference of said spectrometer to be modulated at the vibrational frequency. When used in the FTIR application, it is preferred to avoid such an optical path difference being modulated at the vibrational frequency. In other examples, similar vibrational motions in other grooved-post-mounted optical components (e.g., a retroreflector or an interferometer mounted to a grooved protruding member, such as the grooved protruding member 90 a, 90 b, 90 c, 90 d, 90 e, 90 f, 290, 290 a, 290 b, etc.) can lead to other deleterious vibrational behavior in the systems in which those optical components are employed. Put more simply, the purpose of the grooved post (e.g., the grooved protruding member 90 a, 90 b, 90 c, 90 d, 90 e, 90 f, 290, 290 a, 290 b, etc.) is to mount components into one or more optical assemblies at stable fixed orientations and/or distances from one or more other components. If the posts (e.g., the grooved protruding member 90 a, 90 b, 90 c, 90 d, 90 e, 90 f, 290, 290 a, 290 b, etc.) permit vibration in planes either parallel or perpendicular to their axes, the stable fixed orientation and/or distance feature(s) is defeated.

It was found that, in order to avoid the problem caused by one or more grooved protruding members (e.g., the grooved protruding member 90 a, 90 b, 90 c, 90 d, 90 e, 90 f, 290, 290 a, 290 b, etc.), an improved optical assembly may include a damping ring 400 disposed in or on, and/or adhered to, the groove (e.g., the groove 94 a, 94 b, 94 c, 94 d, 94 e, 94 f, 294, etc.) of the protruding member (e.g., the grooved protruding member 90 a, 90 b, 90 c, 90 d, 90 e, 90 f, 290, 290 a, 290 b, etc.). Preferably, the damping ring 400 is sized and shaped to fill at least a portion (as best seen in FIG. 14) and/or the entire volume or area (as best seen in FIG. 15) occupied or created by the groove (e.g., the groove 94 a, 94 b, 94 c, 94 d, 94 e, 94 f, 294, etc.). The damping ring 400 may be substantially 0-shaped. The size and shape of the damping ring 400 may be defined by the size and shape of the groove (e.g., the groove 94 a, 94 b, 94 c, 94 d, 94 e, 94 f, 294, etc.). Additionally or alternatively, the damping ring 400 may extend beyond or fill additional space outside of the groove (e.g., the groove 94 a, 94 b, 94 c, 94 d, 94 e, 94 f, 294, etc.) in one or more additional embodiments. The damping ring may be made of polyurethane or any other compound that operates to achieve the desired vibrational damping effect and/or to provide the desired structural attribute of creating the vibrational damping effect. Preferably, the damping ring is affixed or connected to the groove (e.g., the groove 94 a, 94 b, 94 c, 94 d, 94 e, 94 f, 294, etc.) by bonding, adhering or fusing. Preferably, the polyurethane ring 400 is bonded on three surfaces, to the face of the mounted component (e.g., the optical structure 20) proximal to the necked-down post (or the grooved protruding member 90 a, 90 b, 90 c, 90 d, 90 e, 90 f, 290, 290 a, 290 b, etc.), to the face of the groove (e.g., the groove 94 a, 94 b, 94 c, 94 d, 94 e, 94 f, 294, etc.) distal to the component (e.g., the optical structure 20) being mounted, and to the shaft (inner face) of the groove (e.g., the groove 94 a, 94 b, 94 c, 94 d, 94 e, 94 f, 294, etc.). Polyurethane is a polymer known to have damping (dissipative) properties to vibrational motion. Other compounds having damping (dissipative) properties may be used as well, such as, but not limited to, any polymer material (or sand) that may be molded into the groove (e.g., the groove 94 a, 94 b, 94 c, 94 d, 94 e, 94 f, 294, etc.) with an adhesive. Preferably, the ring 400 is not rigid, but, in one or more embodiments, the ring 400 may be rigid. As predicted by the inventors of the present invention and as conducted via one or more experiments, the vibrational modes associated with the necked-down posts (e.g., the grooved protruding members 90 a, 90 b, 90 c, 90 d, 90 e, 90 f, 290, 290 a, 290 b, etc.) were greatly minimized, allowing the inventors of the present invention to take advantage of the post mounting concept without significant increased vibrational sensitivity.

FIGS. 14-15 show two three-dimension models showing: (1) an interferometer (e.g., the optical structure 20) mounted with a post (e.g., the protruding members 90 a, 90 b, 90 c, 90 d, 90 e, 90 f, 290, 290 a, 290 b, etc.) having the damping ring 400 disposed in and/or adhered to the groove (e.g., the groove 94 a, 94 b, 94 c, 94 d, 94 e, 94 f, 294, etc.) (see FIG. 14); and (2) a retroreflector (e.g., the optical structure 20) mounted with a post (e.g., the protruding members 90 a, 90 b, 90 c, 90 d, 90 e, 90 f, 290, 290 a, 290 b, etc.) having the damping ring 400 disposed in and/or adhered to the groove (e.g., the groove 94 a, 94 b, 94 c, 94 d, 94 e, 94 f, 294, etc.) (See FIG. 15).

At least one primary function of the ring 400 is to improve the vibrational resistance and/or resistance to the one or more other stresses discussed herein of the grooved post (e.g., the protruding members 90 a, 90 b, 90 c, 90 d, 90 e, 90 f, 290, 290 a, 290 b, etc.) mounting. As illustrated in FIG. 16, when the post (e.g., the protruding members 90 a, 90 b, 90 c, 90 d, 90 e, 90 f, 290, 290 a, 290 b, etc.) tries to vibrate by bending in a plane containing the post (e.g., the protruding members 90 a, 90 b, 90 c, 90 d, 90 e, 90 f, 290, 290 a, 290 b, etc.) axis, L, the post (e.g., the protruding members 90 a, 90 b, 90 c, 90 d, 90 e, 90 f, 290, 290 a, 290 b, etc.) stretches the ring 400 on one side (e.g., area or side 1601 as shown in FIG. 16) of the groove (e.g., the groove 94 a, 94 b, 94 c, 94 d, 94 e, 94 f, 294, etc.) and compresses the ring 400 on the other side (e.g., area or side 1602 as shown in FIG. 16) such that the stretch-compression action on the ring 400 causes the axis (also referred to as a longitudinal axis of the post or protruding member (e.g., the protruding members 90 a, 90 b, 90 c, 90 d, 90 e, 90 f, 290, 290 a, 290 b, etc.)), L, and/or a portion of the axis, L, to bend to the new position of the angled or bent axis, L_(B) (best seen in FIG. 16). Such a bending tendency may occur under vibration or when subject to one or other stresses as discussed herein. When the material of the post (e.g., the protruding members 90 a, 90 b, 90 c, 90 d, 90 e, 90 f, 290, 290 a, 290 b, etc.) and/or the ring 400 is stretched and/or compressed, mechanical loss may occur, thereby damping results. The stretch-compression action on the ring 400, and the choice of polyurethane or any other compound or material which shows large mechanical losses (conversion of motion to heat, thereby reducing the motion), dampen the vibration and/or one or more other stresses acting thereon. Further, the ring 400 may be (and is preferably as discussed above) adhesively adhered to the post (e.g., the protruding member 90 a, 90 b, 90 c, 90 d, 90 e, 90 f, 290, 290 a, 290 b, etc.) on two surfaces thereof and to the mounted component (e.g., the optical structure 20) on a third surface thereof. Such adhesive connection permits the ring 400 to act like a dampening element on the post (e.g., the protruding member 90 a, 90 b, 90 c, 90 d, 90 e, 90 f, 290, 290 a, 290 b, etc.) in the portion of the motion where it tries to stretch the adhered ring 400. In the absence of adhesively adhering the ring 400 to the post (e.g., the protruding members 90 a, 90 b, 90 c, 90 d, 90 e, 90 f, 290, 290 a, 290 b, etc.), the effectiveness of the ring 400 would be lessened because it would lose contact with the post (e.g., the protruding members 90 a, 90 b, 90 c, 90 d, 90 e, 90 f, 290, 290 a, 290 b, etc.) on one side during the stretching cycle. In such an embodiment, the adhesive acts to prevent slippage, enhancing the aforementioned tension/stretch-compression effect so that the one or more stresses may be dampened. In one or more embodiments, the ring 400 may be employed in a groove (e.g., the groove 94 a, 94 b, 94 c, 94 d, 94 e, 94 f, 294, etc.) without adhesive. Either way, the presence of the ring 400 in the post (e.g., the protruding members 90 a, 90 b, 90 c, 90 d, 90 e, 90 f, 290, 290 a, 290 b, etc.) reduces the tendency of the post (e.g., the protruding members 90 a, 90 b, 90 c, 90 d, 90 e, 90 f, 290, 290 a, 290 b, etc.) and/or the groove (e.g., the groove 94 a, 94 b, 94 c, 94 d, 94 e, 94 f, 294, etc.) thereof to stretch and/or compress.

The present invention and one or more components thereof also may be used in conjunction with any suitable optical assembly including, but not limited to, optical assembly structures, interferometers, and/or retroreflectors such as those disclosed in U.S. Pat. Nos. 5,335,111; 5,949,543; 6,141,101; 6,473,185; 6,729,735; 6,752,503; 6,786,608; 6,827,455; 6,945,661; 7,168,817; 7,995,208; 8,092,030; 8,454,176; 8,567,968 to Bleier; U.S. Pat. No. 7,268,960 to Vishnia; U.S. Pat. Nos. 8,120,853; 8,205,852 and 8,205,853 to Jacobson et al.; and U.S. application Ser. No. 13/682,801, filed on Nov. 21, 2012, U.S. application Ser. No. 13/682,857, filed on Nov. 21, 2012, (presently pending), U.S. application Ser. No. 13/682,983, filed on Nov. 21, 2012, (presently pending), U.S. application Ser. No. 13/348,723, filed on Jan. 12, 2012, (presently pending), U.S. application Ser. No. 13/560,510, filed on Jul. 27, 2012, (presently pending), U.S. application Ser. No. 13/560,583, filed on Jul. 27, 2012, (presently pending), U.S. application Ser. No. 13/036,506, filed on Feb. 28, 2011, (presently pending), U.S. application Ser. No. 13/777,267, filed on Feb. 26, 2013 (presently pending), and U.S. application Ser. No. 13/965,333, filed on Aug. 13, 2013 (presently pending), each of which patents and applications are incorporated by reference herein in their entireties. One construction for a hollow retroreflector is as disclosed in U.S. Pat. No. 3,663,084 to Morton S. Lipkins.

Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention. 

1. A method of mounting an optical structure, comprising the steps of: forming and/or providing an optical structure comprising at least one mirror panel, said at least one mirror panel having at least one reflective surface and at least one back surface substantially opposite said reflective surface, wherein said back surface has a protruding member being part of a mount for mounting said optical structure, said protruding member having a first portion extending from said back surface of said optical structure, a second portion, and a groove defining said first and second portions on each side of said groove such that said groove of said protruding member dissipates and/or eliminates one or more stresses passing through said mount and affecting said optical structure; connecting, forming, providing, molding, bonding, and/or adhering a damping ring in and/or to at least one of the groove, the protruding member and the optical structure; forming and/or providing an upper element of said mount comprising a first opening extending therethrough, such first opening forming two arms in said upper element, each of said two arms having a head portion and ending at an end thereof; sliding said first opening of said mount around and/or over at least said second portion of said protruding member; and tightening said first opening of said upper element of said mount around said at least said second portion of said protruding member by inserting a tightening mechanism into a second opening located through one of said head portions of said upper element and by further inserting and tightening said tightening mechanism into a third opening in said other head portion of said upper element so that said tightening mechanism draws said two ends of said head portions toward each other.
 2. The method of mounting an optical structure as recited in claim 1, wherein at least one of: (i) the damping ring operates to dampen said one or more stresses affecting the grooved protruding member, thereby improving the stress resistance of the grooved protruding member; (ii) the damping ring operates to handle tension and to stretch and/or flex at and/or on one portion of the damping ring while compressing at and/or on another portion of the damping ring, thereby improving the stress resistance of the grooved protruding member; (iii) the damping ring is flexibly resilient such that the damping ring operates to return to its rest position and/or original configuration in the grooved protruding member when said one or more stresses are not acting on the damping ring; (iv) the damping ring comprises polyurethane and/or any other compound or material which shows one or more large mechanical losses, thereby at least one of reducing motion, dampening the one or more stresses affecting the grooved protruding member and damping one or more results of the mount; (v) the damping ring operates to reduce the tendency of at least one of the grooved protruding member and the groove to stretch and/or compress; (vi) at least one of one or more portions of the grooved protruding member and one or more portions of the damping ring bend along, transversely to and/or away from an axis of the grooved protruding member and/or a plane including the axis of the grooved protruding member, the axis of the grooved protruding member extending through the first portion and the second portion of the grooved protruding member; (vii) at least one of one or more portions of the grooved protruding member and one or more portions of the damping ring bend along, transversely to and/or away from a longitudinal axis of the grooved protruding member and/or a plane including the axis of the grooved protruding member, the longitudinal axis extending through a surface of the first portion of the grooved protruding member that is in contact with the optical structure and through a surface of the second portion of the grooved protruding member, the surface of the second portion of the grooved protruding member being located on the opposite side of the grooved protruding member from the surface of the first portion of the grooved protruding member and the surfaces of the first and second portions of the grooved protruding member being substantially parallel to each other; (viii) the one or more large mechanical losses comprise a conversion of motion to heat, thereby reducing any motion of the grooved protruding member and/or any other portion of the mount that would result from the one or more stresses and dampening the one or more stresses affecting the grooved protruding member; and (ix) said one or more stresses comprise at least one of: connection and/or clamping stress in between said first and second arms, stress from said tightening of said tightening element, stress from rotating said tightening element, stress passing through said upper element, stress passing through said protruding member, sheer stress, rotational stress and vibrational stress.
 3. The method of mounting an optical structure as recited in claim 2, further comprising at least one of: (i) adhering, molding and/or bonding the damping ring to at least one of the grooved protruding member and the optical structure using an adhesive or bonding material and/or element; (ii) adhesively adhering the damping ring to the grooved protruding member; (iii) adhesively adhering the damping ring to the optical structure; (iv) adhesively adhering the damping ring to the grooved protruding member on and/or at at least one surface of the damping ring; (v) adhesively adhering the damping ring to the grooved protruding member on and/or at at least two surfaces of the damping ring; (vi) adhesively adhering the damping ring to the grooved protruding member on and/or at at least one surface of the damping ring and to the optical structure on and/or at at least another surface of the damping ring; (vii) adhesively adhering the damping ring to the grooved protruding member on and/or at at least two surfaces of the damping ring and to the optical structure on and/or at at least a third surface of the damping ring; and (viii) disposing the damping ring in the mount without the use of the adhesive or bonding material and/or element.
 4. The method of mounting an optical structure as recited in claim 3, wherein the adhesive or bonding material and/or element operates to prevent slippage of the damping ring from the mount, thereby enhancing at least one of the dampening of the one or more stresses affecting the grooved protruding member and the tension, stretch, flex and/or compression effect of the damping ring.
 5. The method of mounting an optical structure as recited in claim 1, further comprising the step of integrally forming said protruding member with at least one of: said at least one mirror panel, said back surface of at least one mirror panel, said optical structure and a back surface of said optical structure.
 6. The method of mounting an optical structure as recited in claim 1, further comprising the step of bonding said first portion of said protruding member to at least one of said back surface of said at least one mirror panel, said at least one mirror panel, said optical structure and a back surface of said optical structure.
 7. The method of mounting an optical structure as recited in claim 6, wherein the step of bonding said first portion of said protruding member to said back surface of said at least one mirror panel comprises at least one of: fusing and adhering.
 8. The method of mounting an optical structure as recited in claim 1, further comprising disposing said groove on said protruding member such that said first portion of said protruding member is smaller than said second portion of said protruding member.
 9. The method of mounting an optical structure as recited in claim 8, further comprising: placing a surface of said first portion of said protruding member in contact with said back surface of said optical structure; and sizing and/or shaping said surface of said first portion of said protruding member such that said surface of said first portion has at least one of: (i) a smaller diameter than a lateral cross-section and/or a bottom surface of said second portion of said protruding member that is disposed in said first opening of said upper element; and (ii) a smaller surface area than a lateral cross-section and/or a bottom surface of said second portion that is disposed in said first opening of said upper element.
 10. The method of mounting an optical structure as recited in claim 8, further comprising sizing and/or shaping at least one of said first portion of said protruding member and said second portion of said protruding member such that said first portion of said protruding member has a smaller volume than said second portion of said protruding member.
 11. The method of mounting an optical structure as recited in claim 1, further comprising the step of forming a base element of said mount with said upper element of said mount.
 12. The method of mounting an optical structure as recited in claim 11, wherein at least one of: (i) said base element includes a mounting structure for mounting said mount to another structure; (ii) said upper element extends from said base element; (iii) said base element is formed integrally with said upper element; (iv) said one or more stresses comprises at least one of: connection and/or clamping stress in between said first and second arms, stress from said tightening of said tightening element, stress from rotating said tightening element, stress passing through said base element, stress passing through said upper element, stress passing through said protruding member, sheer stress, rotational stress and vibrational stress; (v) said base element extends from said upper element at an angle such that said base element and said upper element are at least one of: not substantially co-linear and/or co-planar; and substantially co-linear and/or co-planar; (vi) said integrally formed upper and base elements of said mount being a metal alloy having a low coefficient of thermal expansion comprising at least one of aluminum and a nickel iron alloy having a low coefficient of thermal expansion; (vii) said base element is at least one of: any geometric shape, any geometric shape such that said base element has a smaller volume than said upper element, chamfered, sloped and tapered; and (viii) said mounting structure comprises at least one of: (a) a threaded member extending from said another structure for cooperative screwed attachment within a threaded opening in said upper element; and (b) a threaded member extending from said upper element for cooperative screwed attachment within a threaded opening in said another structure.
 13. The method of mounting an optical structure as recited in claim 11, further comprising the step of forming supporting means for said base element of said mount for securing said optical structure to a support structure.
 14. The method of mounting an optical structure as recited in claim 13, wherein said supporting means comprises at least one of: (i) a threaded member extending from said support structure for cooperative screwed attachment within a threaded opening in said base element; and (ii) a threaded member extending from said base element for cooperative screwed attachment within a threaded opening in said support structure.
 15. The method of mounting an optical structure as recited in claim 1, further comprising sizing and/or shaping said groove such that the groove is at least one of: (i) a space between said optical structure and at least one of said second portion of said protruding member and said upper element of said mount such that said optical structure is spaced away from said at least one of said second portion of said protruding member and said upper element; and (ii) operating to achieve and/or maintain at least one of: dimensional stability, a predetermined degree of flatness and a high degree of flatness of at least one of: about λ/10, about λ/15, about λ/20, about λ/30, between about λ/10 and about λ/15, between about λ/10 and about λ/20, between about λ/10 and about λ/30, between about λ/15 and about λ/20, between about λ/15 and about λ/30 and between about λ/20 and about λ/30.
 16. The method of mounting an optical structure as recited in claim 1, further comprising: extending said groove of said protruding member along a perimeter of said first portion of said protruding member; and sizing and/or shaping said groove such that the groove is at least one of: (i) having a substantially circular shape; (ii) being of any geometric shape; and (iii) including at least one of: one or more right angles, one or more slopes, one or more chamfered surfaces having a consistent slope, one or more chamfered surfaces having a changing convex slope, one or more chamfered surfaces having a changing concave slope, and one or more tapers.
 17. The method of mounting an optical structure as recited in claim 1, further comprising forming said groove at substantially a right angle such that a first portion of an outer surface of said protruding member extends from said second portion of said protruding member inwardly substantially parallel to said surface of said first portion of said protruding member and a second portion of said outer surface of said protruding member extends from the first portion of said outer surface vertically substantially at a right angle and/or perpendicular to said surface of said first portion of said protruding member.
 18. The method of mounting an optical structure as recited in claim 1, further comprising forming at least two extensions that are in communication with said groove and are extending from said first portion of said protruding member such that a recess is defined between the at least two extensions for said optical structure to be positioned therein.
 19. The method of mounting an optical structure as recited in claim 18, further comprising sizing and/or shaping said at least two extensions such that said at least two extensions at least one of: (i) do not extend outwardly beyond said first portion of said protruding member; and (ii) taper and/or slope inwardly away from said groove towards said optical structure.
 20. The method of mounting an optical structure as recited in claim 1, further comprising forming one or more reliefs such that said one or more reliefs are in communication with at least one of: (i) said first opening, said one or more reliefs being positioned in and/or on a perimeter of said first opening and said one or more reliefs operating to reduce physical contact between one or more surfaces of said protruding member and one or more surfaces of said upper element of said mount, thereby reducing and/or eliminating transfer of one or more stresses between said upper element of said mount and said protruding member; and (ii) at least said second portion of said protruding member, said one or more reliefs being positioned in and/or on a perimeter of said at least said second portion of said protruding member and said one or more reliefs operating to reduce physical contact between one or more surfaces of said protruding member and one or more surfaces of said upper element of said mount, thereby reducing and/or eliminating transfer of one or more stresses between said upper element of said mount and said protruding member.
 21. The method of mounting an optical structure as recited in claim 20, wherein said one or more reliefs are formed such that: (i) said one or more reliefs extend a predetermined distance radially from said first opening towards an exterior of said upper element when said one or more reliefs are positioned in and/or on said perimeter of said first opening; and (ii) said one or more reliefs extend a predetermined distance radially from said at least second portion of said protruding member towards an interior of said protruding member when said one or more reliefs are positioned in and/or on said perimeter of said at least said second portion of said protruding member.
 22. The method of mounting an optical structure as recited in claim 1, wherein said first portion of said protruding member has a surface that is in contact with said surface of said optical structure and said groove is spaced away from said optical structure such that said groove is disposed at a location along said protruding member that is at a predetermined distance from said surface of said first portion.
 23. The method as recited in claim 1, wherein at least one of: said optical structure is taken from the group consisting of: one or more hollow retroreflectors, one or more solid retroreflectors, one or more mirror panels, one or more optical filters, one or more interferometers and one or more roof mirrors; said optical structure comprises at least one of at least one mirror panel, at least one mirror panel having a reflective surface and a back surface where said back surface extends in a plane substantially parallel to a plane of said reflective surface, a reflective panel, a refractive panel, an optical filter and at least two reflective panels that operate to at least one change a direction of light and retroreflect light; said at least two reflective panels each have at least one reflective surface and at least one back surface substantially opposite said reflective surface; said protruding member and/or said first portion of said protruding member extends from said back surface of at least one of said at least two reflective panels; said optical structure has at least one reflective surface and at least one back surface, said at least one back surface extending in a plane substantially parallel to a plane of said at least one reflective surface; said protruding member and/or said first portion of said protruding member extends from said at least one back surface of said optical structure; said protruding member is disposed between said optical structure and said upper element such that said optical structure is at least one of disposed on and in connection with a part of said first portion of said protruding member and said upper element is disposed at least one of substantially on, in connection with and around at least part of said second portion of said protruding member; said protruding member comprises a solid cylinder; said first and second portions of said protruding member are solid; and said optical structure is centered in said recess.
 24. The method as recited in claim 23, wherein said protruding member and/or said first portion of said protruding member is at least one of: (i) integrally formed with said back surface of at least one of said at least one mirror panel, said at least one of said at least two reflective panels and/or said optical structure; and (ii) bonded to said back surface of at least one of said at least one mirror panel, said at least one of said at least two reflective panels and/or said optical structure. 